Half working? Don't you think that's a bit of a stretch? It's working perfectly, at least so far.
Yes there are bugs but they are so minor that they don't even matter.
Known bugs
3GS new bootrom is broken, fix pending: Doesn't affect people with an iPhone 4
Some people need to restart to get the Cydia icon to show up after installing: Restart the phone, how much easier can it be?
Some people still don't have windows: Is he talking about Microsoft Windows here? How is this even a bug?
Beta iOS versions aren't supported: Again...only affects a small handful of people
Uninstall in limera1n app doesn't work, you can just delete the blackra1n.app directory, i need regression testing: Easy to do with SSH. If you don't know how to SSH, you probably shouldn't be dealing with jailbreaking anyway